Electrical rectifier



March 7, 1933. w; p P E 1,900,732

' ELECTRICAL RECTIFIER Filed Sept.'25, 1931 INVENTOR.

an; m

' ATTORNEY.

Patented Mar. ,7, 1933 UNITED STATES PATENT, OFFICE WILLARD 2. uses, orwILxr'NsBURe, PENNSYLVANIA, Assre on TO THE UNIoN swrrcn & SIGNALCOMPANY, or swxssvA E, PENNSYLVANIA, A CORPORATION 01 PENNSYLVANIAmurmur. ancrrrmn.

Application filed September 25, 1981. Serial No. 565,094,

My invention relates to electrical rectifiers, and particularlytorectifiers employing asymmetric units of the metal oxide type.

It has been proposed to utilize rectifiers of this type in various kindsof radio circuits as detectors of high frequency waves and for otherpurposes. When utilized inthis manner, it is usually desirable that therectifier should have a high resistance as well as a 00d rectifyingratio, and that the rectifier s ould take up as little space aspossible@ One way in which the rectifier can be constructed to havethese desirable characteristics is to make the asymmetric units small inphysical size. ,Forexample, units one-twelfth of an inch in diameterhave been found to be very satisfactory, When the units are made smallin physical size, however, and several units are assembled'together intoa stack, considerable difficulty has been experienced in securing goodelectrical contact between the units, and in making external electricalconnections with the units. One object of my invention is to provide arectifierof the type described in which these difiiculties are;completely eliminated.

Another object of my invention is to provide a rectifier of thefour-legged bridge type which can be plugged into any of the well-knownforms of vacuum tube sockets,

and which will utilize a minimum amount of space.

I will describe one form of rectifier embodying my invention, and willthen point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a view showing in side elevationone form of rectifier embodying my invention. Fig. 2 is a top plan view,on an enlarged. scale,

of the rectifier shown in Fig. 1; Figs. 3 and 4 are vertical sectionalviews taken-on the lines III-III and IV-IV, respectively, of Fig. 2.Fig. 5 is a side View showing, on an enlarged scale, one of theasymmetric units B forming part of the rectifier shown inFigs. 1 to 4,inclusive, and Fig.- 6 is a top plan view of the asymmetric unit B shownin Fig. 5. Fig. 7 is a side view Similar reference characters refer tosim-' ilar parts in each of the several views.

Referring first to Figs. 1 to 4, inclusive, the rectifier here shown isof the, fourlegged bridge type, and comprises ,four stacks A A A and Aof asymmetric units B assembled in four holes 3, 4, 5 and 6,respectively, formed in a block 7 of suitable insulating material, suchas a condensation product of phenol. Ihe block 7 may have any desiredshape and size, but in. the embodiment illustrated, the block 7 iscylindrical, and is of suitable size to permit the rectifier to beplugged into any of the wellknown push types of vacuum tube sockets, aswill be explained more fully hereinafter. The holes 3, 4, 5 and 6 extendvertically downward, through the block 7, and are spaced apart the samedistance as the contact holes in a Vacuum tube socket of the typepreviously referred to. The lower ends of the holes 3 and 6 are closedby a semicircular I metal contact plate 8, and the lower ends offastened to the block 7 by means of termlnal members 15 and 16, whichalsofasten the semicircular metal plates 10 and 11 to the block 7. Theterminal members 13 and 14 are similar, and are each provided with anannular shoulder 12 which engages the underside of the circularinsulating plate 12, and with a threaded portion 6 which extendsupwardly through the insulat ng plate 12, and is screwed into a suitablethreaded hole in the associated semicircular plate 8 or 9. The'terminalmembers 15 and 16 are likewise similar, and are each provided with anannular shoulder b which engages the underside of the plate 12, and

with a threaded portion (1 which extends upwardly through the insulatingplate 12 and through the block 7, and is screwed into a suitablethreaded hole in the associated plate or 11. The lower ends of theterminal members 13, 14, 15 and 16, as here shown, are each providedwith a prong 0:, these prongs being so spaced and so proportioned as toenable the rectifier to be plugged into a Vacuum tube socket of the typereferred to hereinbefore, in only one position. It should bedistinctivelyunderstood, however, that my invention is not limited tothe particular type of terminal members shown, and that these terminalmembers may, if desired, assume the form of binding posts so constructedthat the conductors of any circuit in which the rectifier is to beutilized may be connected directly to the terminal members in the mostconvenient manner.

The asymmetric units B may be of any suitable type, and as most'clearlyshown in Figs. 5 and 6, each unit, in the form here shown, comprises afiat disk 1 of metal, such as copper, having a coating 2 of a compoundof the metal, such as cuprous oxide, formed on one side thereof.Asymmetric units of the type described exhibit the characteristic ofofiering a higher resistance to current which tends to flow through the,unit from the copper to the oxide than to current tending to flow in theopposite direction through the unit. The coating 2 may, if desired,cover the wholeside of the unit, but in. the

7 preferred form, the coating only covers a circular central portion,leaving an annular uncoated portion adjacent the outer edge of the unit,as clearly shown in the drawing. One reason for constructing the unitsin the manner shown and described is that with a given load on a unit,the smaller the area of the coating is, the higher the resistance andrectifyingratio of the unit will be. Another reason for constructing theunits in the manner described is that, when the whole face of a unit ofthe size contemplated in rectifiers embodying my invention is coated,

- it is difiicult to prevent some of the oxide past the edge of thecoating into Contact with the metal'part of the unit, because, if

this should occur, the asymmetric unit would be short circuited, and therectified would therefore fail to operate in the manner intended. Inorder to enable each conducting member C to engage as large an area ofthe coating-2 of the adjacent unit as possible, and yet prevent theconducting members from short circuiting the units, I prefer toconstruct each conducting member in the form of a frustum of a cone (seeFigs. 7 and 8), the larger base of which has a diameter which is onlyslightly smaller than the diameter of the holes in which the units areassembled, and the smaller base of which has the same, or a slightlysmaller diameter than the outer surface of the coating 2 of the units.\Vith this construction it will be seen that the shape, ofthe conductingmembers keeps these members properly centered on the coating of theadjacent units and provides the maximum contact area between the membersand the units. It should be pointed out, however, that a frustum of acone is not the only shape that the conducting member C may assumeinorder to provide the desired contact between'the units, the onlyessential requirement being that the conducting member have a large endfor centering the members and a small end for making contact with thecoated side of the un1ts.

Interposed between the .upper end of each stack A of asymmetric unitsand the plate which closes the hole in which such stack is mounted, is aconducting plunger 17 and a compressed coil spring 18. The function ofthe springs 18 and conducting plungers 17 is to subject the asymmetricunits B and the associated conducting members C to a comparatively highpressure, thus insuring good electrical contact between the units, theconducting members, and the contact plates which close the holes inwhich the units and conducting members are mounted.

As shown in the drawing, each stack A of asymmetric units comprises fiveasymmetric units in series, the units of the stacks A and A beingassembled with their coating 2 up, so that these stacks will offer thelowest resistance to current tending to flow downwardly through thestacks, and the units of the stacks A and A being assembled with theircoating 2 down so that these stacks will offer the lowest resistance tocurrent tending to flow upwardly through the stacks. It should beunderstood, however, that the particular arrangement shown is chosenmerely for convenience in illustrating my invention, and not by way oflimitation, the number of stacks and arrangement of units in each stackbeing determined by the manner in which the rectifier is to be utilized.

In utilizing the rectifier, a source of alternating current may beconnected with the 2 terminal members 13 and 14 and the load may beconnected with the terminal members 15 and 16. With this arrangement,the terminal member 15 will be negative and the terminal member 16 willbe positive.

In order to facilitate inspection and assembly of the units, the block 7may, if desired, be provided with a plurality of vertically disposedslots 19, one of which extends through the side of the block into eachhole 3, 4, 5 and 6, as shown in Figs. 1 and 2.

Although I have herein shown and described only one form of electricalrectifier embodying my invention, it is understood that various changesand modifications may be made therein within the scope of the appendedclaims withoutdeparting from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. A rectifier comprising an asymmetric unit consisting of a flat metalmember having a coating of a compound of the metal formed on one sidethereof, an insulating member provided with a hole which receives saidunit with'slight clearance, an impressionable conducting member in saidhole having one end which fits into said hole with only slight clearanceand another end which is somewhatsmaller in size than the coating ofsaid unit and which engages said coating,.

, and means for subjecting said member and said unit to a comparativelyhigh pressure.

2. A rectifier comprising an asymmetric unit consisting of a flat metalmember having a coating of a compound of the metal formed on one sidethereof, an insulating member provided with a'hole which receives saidunit with slight clearance, an impressionable conducting member in saidhole having one end which fits into said hole, with only slightclearance and another end which is somewhat smaller in size than thecoating of said unit and which engages said coating, a coiled spring insaid hole, and means including said spring for subjecting said mem herand said unit to a comparatively high pressure,

3. A rectifier comprising a block of insulating material provided with ahole, an asymmetric unit in said hole, said asymmetric unit comprising ametal disk having a coating of a compound of the metal formed on oneside thereof, an impressionable conducting member in said hole, saidmember being in the form of a frustum of a cone and having its smallerend engaging the coating ofsaid unit, and means for subject- 'ing saidmember and said unit to a comparatively high pressure.

4. A rectifier comprising a block of 1nsulating material provided with ahole, an.

asymmetric unit in said hole, said asymmetric unit comprising a metaldisk having a coating of a compound of the metal formed on one sidethereof, an impressionable conducting member in said hole, said memberbeing inthe form of a frustum of a cone and having its smaller endengaging the coating of said unit, a spring in said hole, and meansincluding said spring for subjecting said unit and said member to acomparatively high pressure. a

5. A rectifier comprising a block of insulating material provided with ahole, an asymmetric unit in said hole, said asymmetric unit comprising ametal disk having a coating of a compound of the metal formed on oneside thereof, an impressionable conducting member in said hole, saidmember being in the form of a frustum of a cone the one base of whichfits into said hole with a small amount of clearance and the other baseof which has a diameter which is smaller than the diameter of thecoating of said unit, said smaller base being in engagement with thecoating of said unit, and means for subjecting said member and said unitto a comparatively high pressure.

6. A rectifier comprising a block of insulating material provided with ahole, an asymmetric unit in said hole, said asym metric unit comprisinga metal disk having a coating of a compound of the metal formed on oneside thereof, an impressionable conducting member in said hole, saidmember being in the form of a frustum of a cone the one base of whichfits into said hole with a small amount of clearance and the other baseof which has a diameter which is smaller than the diameter of thecoating of said unit, said smaller base being in engagement with thecoating of said unit, a spring in said hole, and means including saidspring for subjecting said member and said unit to a comparatively highpressure.

- 7. A rectifier comprising a block of insulating material provided witha hole which extends through said block, an asymmetric unit in saidhole, said asymmetric unit comprising a metal disk having a coating of acompound of the metal formed on one side thereof, an impressionableconducting member in said hole, said member being in the form of afrustum of a cone and having its smaller end engaging the coating ofsaid unit, two metal plates secured to said block and closing each endof said hole, and a compressed spring in said hole for subjecting saidunit and said member to a comparatively high pressure.

8. A rectifier comprising a block of insulating material provided with ahole, a plurality of asymmetric units in said hole each said unitcomprising a metal disk having a coating of a compound of the metal afrustum of a cone and each having its smaller base engaging the coatingof a different one of said units, a compressed spring in said hole, andmeans, including said spring for sub ecting said units and said formedon one side thereof, a plurality of impressionable conducting members insaid hole each said member being in the form of a frustum of a cone andeach having its smaller base engaging the coating of a different one ofsaid units, a spring in said hole, and means for compressing said springto subject said units and said members to a comparatively high pressure.

10. A rectifier compri*'ng.a block of insulating material provided witha hole which extends through said. block, an asymmetric unit in saidhole, said asymmetric unit comprisinga metal disk having a coating of acompound of the -metal formed on one side thereof, an impressionableconducting member in said hole, said memberbeing in the form of afrustum of a cone and having its smaller end engaging the coating ofsaid unit, two metal contact plates secured to said block one closingeach end of said hole and ,a compressed spring in said hole forsubjecting said unit and said member to a comparatively high pressure,and means for making electric connections withsaid plates.

11. As a new article of manufacture, an impressionable electricalconducting memher for improving the contact between a second conductingmember and an asymmetric unit of the dry disk type, said impressionableconducting member being in the form of a frustum of a cone the largerbase of which has substantially the same diameter as the secondconducting member, and the smaller base of which has a diameter which issomewhat smaller than the diameter of the unit.

12. Asa new article of manufacture, an impressionable electricalconducting member for improving the contact between a second conductingmember and an asymmetric unit of the type comprising-a fiat metal memberhaving a coating of a compound of the metal formed on a portion of oneside thereof, said impressionable conducting member being in the form ofa frustum of a solid the larger base of which has substantially the sameshape and area as the metal side of the unit, and the smaller base ofwhich has the same shape but a slightly smaller area than the coating ofthe unit.

13. As anew article of manufacture, an

impressionable electrical conducting member for improving the contactbetween 'a second conducting member and an asymmetric unit of the typecomprising a metal disk having a centrally located circular coating of acompound of the metal formed on one side thereof and covering only aportion vof such side, said impressionable conducting member being inthe form of a frustum of a cone the larger base of which has the samediameter as the disk, and the smaller ,base of which has adiameter whichis somewhat smaller-than the diameter of the coating.

14. An electrical rectifier comprising a block of insulating materialhaving a first, a second, a third, and a fourth hole extendingthcrethrough in spaced relation, a first metal plate secured to saidblock and closing one end of said first and second holes, a second metalplate secured to said block and closing the one end of said third andfourth holes, a third metal plate securedto said block and closing theother end of said second and third holes, a fourth metal plate securedto said block and closing the other 'end of said first and fourth holes,four stacks of asymmetric units one located in each of said holes andeach comprising one leg of the rectifier, and a compressed spring ineach of said holes for subjecting the units of the'associated stack to arelatively high pressure.

15. An electrical rectifier comprising a block of irsulating materialhaving a first, a second, a third, and a fourth hole extendingtherethrough in spaced relation, a first metal plate secured to saidblock and closing one end of said first and second holes, a second metalplate secured to said block and closing the one end of said third andfourth holes, a third metal plate secured to said block and closing theother end of said sec- 0nd and third holes, a fourth metal plate securedto said block and closing the other .end of said first and fourth holes,four stacks of asymmetric units one located in each of said holes andeach comprising one leg of the rectifier, each said asymmetric unitcomprising a metal disk having a coating of a compound of the metalformed on one side thereof, a plurality of impressionable conductingmembers each being in the form of a frustum of a cone the larger base ofwhich has a diameter only slightly smaller than the diameter of theholes in said block, one said conducting member being disposed in eachof said holes adjacent each unit and each having its smaller baseengaging the coating of the adjacent unit, and four springs onecompressed in each of said holes for subjecting the units and theconducting members to a comparatively high presure.

16. An electrical rectifier comprisin a block of insulating materialhaving a rst,

a; second, a third, and a fourth hole extending therethrough in spacedrelation, 0. first metal plate secured to said block and closing one endof said first and second holes, a second metal plate secured to saidblock and closing the one end of said third and fourth holes, a thirdmetal plate secured to said block and closing the other end of saidsecond and third holes, a fourth metal plate secured to said block andclosing the other end of said first and fourth holes, four stacks of.asymmetric units one located in each of said holes and each comprisingone leg of the rectifier, eachsaid asymmetric unit comprising a metaldisk having a coating of a compound of the metal formed on one sidethereof, a plurality of impressionable conducting members each being inthe form of a frustum of a cone the larger base of which has a diameteronly slightly smaller than the diameter of the holes in said block, onesaid conducting member being disposed in each of said holes adjacenteach unit and each having its smaller base engaging the coating of theadjacent unit, four metal lungers one located in each of said holestween one end of the associated stack and 1 the plate which closestheadjacent end of the hole, and four compressed coil springs oneinterposed between each plunger and the late which closes the adjacentend of the hole for subjecting the units of the as sociated stack to arelatively high pressure.

17 An electrical rectifier comprisin a block of insulating materialhaving a rst, a second, a third, and a fourth hole extendingtherethrough from one end to the other in spaced relation, a first metalplate engagin one end of said block and closing one en of said first andsecond holes, a second metal plate engaging said one end of said blockand closing one end of said third and fourth holes, a third metal plateengaging the other end of said block and closing the other end of saidsecond and third holes, a fourth metal plate engaging said other end ofsaid block and closing the other end of said first and fourth holes, aninsulating plate engaging the outer side of said'third and fourth metalplates, two terminal members for fastening said first and second metalplates and said insulatin plate to said block each said terminal mem rbeing rovided with a shoulder which engages t e outer side of said blockand each extending through said insulating plate and one having one endscrewed into said first plate and the other having one end screwed intosaid second plate, two other terminal members for fastening said thirdand fourth plates to said insulating plate, each said other terminalmember being provided with a shoulder which engages the outer sideofsaid insulating plate and each extending through said insulating plateand one having one in each of said holes, the asymmetric units a of eachstack each comprising a metal disk having a coating of a compound of themetal formed on one side thereof, the units of the stacks in said firstand second holes being disposed with their metal sides facing in onedirection and the units of the stacks in said second and third holesbeing disposed with their metal sides facing in the opposite direction,a plurality of impressionable conducting members each being in the formof a frustumof a cone the larger base of which has a diameter onlyslightly smaller than the diameter of the holes in said block, one saidconducting member being disposed in each of said holes adjacent eachunitand each having its smaller base engaging the coating of the adjacentunit, four plungers,

and four compressed springs, one said plunger and one said spring beinglocated in each of said holes between one end 'of the associated stackand the plate which closed the adjacent end of the hole, said springsserving to subject the units and the impressionable conducting membersin the associated stack to a relatively high ressure.

18. As a new article 0 manufacture, an impressionable electricalconducting member for improving the contact between a second conductingmember and an asymmetric unit of the type comprising a flat metal memberhaving a coating of a compound of the metal formed on a portion of oneside thereof, said impressionable conducting member having one basewhich has substantially the same shape and area as the metal side ofsaid unit, and another base which has the same shape and an area whichis equal to, or smaller than, the coating of the unit.

In testimony whereof I aflix my signature.

WILLARD P. PLACE.

